They're used because they're quick: They come with a little color-coded chart that shows which stick for which application. No need to look up torque requirements, just plug it on an air tool and go.
That being said, they don't work as well as a torque wrench. They will break lugs, I can attest to that happening to me at a Les Schwabb.
i think they work as a shock absorber of sorts. you can use a torque satick with an impact wrench and get relatively close to the ftlb you require.
if you used a torque stick with a hand wratchet, you would way overtorque because a torque stick cant limit torque, it just absorbs the multipule tiny blows of an impact wrench.
atleast, this is how i think it works.
they are suppose to have a certain amount of flex close to the point of what they are rated for.
some tires shops like the shop i work at will use them to snug up the lugnuts when the vehicle is off the ground...then as soon as its lowered to the ground we torque them as well.
ya usually the torque stick sets them lower. it depends on teh kind of gun you use though. the shop has a set of rather low powered IR guns. when using those they will torque higher with the torque wrench. however when i use my MATCO 1000ft-lb gun, i very rarely have to retighten them.
the MATCO gun is a lot lighter adn quieter to i use that more often. also when pulling off lugs its a lot faster. personally i try to put some anti seize on the studs on vehicles that break them a lot.
They work well if you run them in a normal power for a short period of time. The problem is that many techs don't know how to use them and can still over or under torque. They should always be double checked with a torque wrench. They are simply for getting it close, they are not a replacment for a torque wrench.
The Tire Industry Association did a study and found that torque sticks limited the amount of torque applied, but that it was highly variable, mostly due to the torque rating of the impact gun - the stronger the gun, the more torque applied. However, it was possible to both under and over torque using a torque stick.
Their conclusion: Use a torque wrench!
Torque sticks use a torsion bar twist theory.In others words they flex at a pre-determined rate then stop applying torque when they get to the flex point.They are quite accurate when used by a installer with a good sense of his tools...but a torque wrench is the the finishing touch for me when I install my tires every change of the seasons.
wow its amazing how many people actually torque the wheels with a wrench after tightening with the torque-stick.
i know that there are a lot of people out there that just use an impact and regular socket!!
Have tightened literally thousands of tires with an impact gun and torque stick and have had nary a problem. Nobodys wheels have fallen off, wheel studs havent broken, etc. The thing to avoid is an impact gun without a torque stick. That will usually make the lugs way too tight and sometimes warp the brake rotors or break the lugs.
I agree with the statement that different impact guns will tighten to different values with the same torque stick. A really strong gun will overpower the torque stick and vice versa with a cheapo weak gun.
I got my kid a tire at a shop which proudly displayed a sign "We hand torque all nuts".
Watched the "tech" use an air wrench, maybe with a torque stick, zap on the nuts. Then he took a hand torque wrench, and much to nobody's surprise, it clicked when turned.
I went out of the shop into the parking lot, loosened the nuts (some of which were much tighter than others--imagine that), and retorqued.
Yes I end retorque all wheels that go on a tire shops. If they don't use a torque wrench and put them on by hand there is a 99% chance they are overtightened. It may not matter to a lot of people, but when your stuck on the side of the road, you'll be much happier if they are not overtightened.